Miri is significantly smaller than KL. It is the 19th largest city in Malaysia, 5th on Borneo. It is significantly smaller, and more comfortable if you're looking for a city you can embrace more easily.
Like most nations in Southeast Asia, there is of course, petty crime. Pickpockets, purse-snatching, and other forms of thievery can occur anywhere. Rape is something that is less common, but can happen. However, I can assure you that by crime rate, Malaysia fares better than Indonesia or Philippines.
All that you'd expect is located here; hospitals, restaurants, markets, malls, etc. It won't have as many choices as KL, but its good enough that tourists keep coming.
Attractions include Gunung Mulu National Park, world famous for it's large caves. It is a famed eco-tourism destination. The Niah Caves are also quite famous. There are also other rainforests, and many coral reefs and sandy beaches. Brunei is not too far, and you can visit that tiny country too.